my @a = qw(1 2 3 4 5);
while ((my $a, @a) = @a) {
    printf "\$a is now '%s', and \@a is now (%s)\n", $a, join(')(',@a);
}

# Output ...
$a is now 1, and @a is now (2)(3)(4)(5)
$a is now 2, and @a is now (3)(4)(5)
$a is now 3, and @a is now (4)(5)
$a is now 4, and @a is now (5)
$a is now 5, and @a is now ()